1. Technical Field
The present invention relates to a screw shaft structure for a twin screw extruder, and more particularly, to a novel improvement for reducing a weight of a raw material, which is used for manufacturing a screw shaft, by combining a tapered section and a tapered ring as a structure of a flange section.
2. Description of the Related Art
As a conventionally used screw shaft structure for a twin screw extruder of this type, the structure disclosed in JP 2005-22091 may be taken as an example.
That is, the above-mentioned screw shaft structure of JP 2005-22091 is configured as illustrated in FIGS. 4 and 5.
Specifically, in FIG. 5, reference symbol 1 represents a screw shaft raw material to be used for manufacturing a screw shaft 2 through a cutting process. The screw shaft raw material 1 has a pair of suspension holes 3 and 4 provided at both ends thereof, and the screw shaft raw material 1 can be transported through the suspension holes 3 and 4.
From the screw shaft raw material 1, a connection section 5 to be connected to a gear reducer of a drive motor (not shown), a ground section 6 formed integrally with the connection section 5, a flange section 7 formed on a downstream side of the ground section 6, and a screw piece inserting section 8 connected to the flange section 7 and to be used for insertion of a plurality of screw segments are formed through the cutting process.
Note that, as illustrated in FIG. 4, two screw shafts 2 are provided in parallel inside a cylinder (not shown) and formed as the twin screw extruder described above.